1. Field of the Invention
The invention relates to a method for specifying defective processes and apparatus in a thin-film device manufacturing process on the basis of inspection information.
2. Description of the Related Art
The manufacture of thin-film devices, such as semiconductors, liquid crystal displays, and hard disk magnetic heads constitutes numerous of processes.
The number of procedures for such processing at times reaches several hundred. When an exterior abnormality, such as extraneous matter or broken wiring, occurs on a thin-film device due to a defect or an abnormality in the manufacturing conditions of the processing apparatus, the probability of defects occurring in a product increases, and yields decrease. Accordingly, specifying the apparatus that generated the problem and taking corrective measures is important for maintaining and enhancing yields. Therefore, inspections, such as extraneous matter inspections and external appearance inspections are carried out for each main process, and monitoring is performed to determine if processing is being carried out properly. Because time and labor constraints currently make it impossible to carry out inspections of all the substrates being processed in each processing procedure, ordinarily, inspections arc performed on samples of processed substrates taken by lot unit, or processed substrate unit, or a combination thereof, for each of a number of sequential processes. The term processed substrate signifies the minimum unit for which product processing is being carried out, and if it is a semiconductor, indicates one wafer.
When extraneous matter and external appearance abnormalities occur frequently, an in-depth analysis for specifying the apparatus generating the abnormality is carried out for the individual substrate in question. For example, a detailed observation of the location provided by an inspection apparatus is carried out, and the process generating the abnormality is inferred by observing the shape of the extraneous matter or its appearance. Further, either a cross section, which intersects one part of an extraneous matter or abnormality, is created, and the layer in which the abnormality occurred is determined, or a spectrum related to an element or element information comprising extraneous matter or a defect is obtained by an appropriate technique, such as EPMA (Electron Probe Micro Analysis), AES (Auger Electron Spectroscopy), micro-Raman spectroscopy or microfluorescence spectroscopy. Analysis is performed thereon; the substance constituting the extraneous matter or defect is specified, and the manufacturing process in which the abnormality most likely occurred is inferred. Then, appropriate countermeasures are taken, e.g. by carrying out maintenance or cleaning. The term xe2x80x9csingular pointxe2x80x9d refers to a point provided as the location where an abnormality was detected. Herein, extraneous matter, an external appearance abnormality or other problem are referred to as a xe2x80x9cdefect.xe2x80x9d
Inferring the process in which an abnormality occurred from external appearance requires the advanced judgment of an analyst, and the individual differences and the time required for a determination are problems. A procedure for automatically classifying defects according to specific rules is disclosed in Japanese Patent Application Laid-Open No. 7-201946.
Further, the problem with specifying the name of a substance according to the spectrum is that it depends to a large extent on the judgment of an analyst, similar to a determination based on external appearance information. It also takes time, and can involve differences of opinion. Procedures for automatically specifying the name of a substance from spectral data are disclosed in Japanese Patent Application Laid-Open No. 63-108253 and Japanese Patent Application Laid-Open No. 8-124982. Further, a procedure for specifying a problem processing apparatus from the correlation between a database related to defects generated by a processing apparatus and data related to a defect acquired by an inspection apparatus is disclosed in Japanese Patent Application Laid-Open No. 2000-222033.
To quickly and accurately specify a processing apparatus that is causing a problem, it is necessary to carry out analysis multiple tests, such as pattern generation of extraneous matter/defects, external appearance, element information, processing history, and the processing log for each processing apparatus. If a processing apparatus includes a plurality of processing units (subsequently described as chambers) for doing the same processing, the processing log for each chamber must be checked.
The fact that a multiple sources of information are used is not mentioned in the conventional procedure for automatically classifying defects by external appearance or the procedure for automatically specifying the name of a substance from spectral data. Further, in the procedure for specifying a processing apparatus, no mention is made of striving to make the procedure more efficient by limiting the time period and apparatus targeted for searching.
The invention provides a method and apparatus for enabling an apparatus that is causing a problem to be quickly specified from product inspection information, in which an abnormality was detected. It also provides a method for analyzing defect information obtained by inspecting work pieces in a thin-film device manufacturing process. The method is constituted such that defects occurring on substrates as a result of carrying out processing are extracted by comparing data obtained by inspecting the processed substrates prior to carrying out processing. This can involve plural processing apparatuses in a thin-film device manufacturing process, and data obtained by inspecting the processed substrates. When the number of extracted defects is greater than a pre-established number, in-depth analysis of the defects is carried out, and the in-depth analysis information, information indicating the processing histories of the processed substrates, and information related to the state of the processing apparatus, are displayed on a screen.
Further, the invention is constituted such that the apparatus causing the problem is extracted by evaluating via computer the correlation between the in-depth analysis information, the processing-history-derived information, and the processing apparatus status-related information. These and other objects, features and advantages of the invention will be apparent from the following detailed description of preferred embodiments of the invention, as illustrated in the accompanying drawings.